This invention is in the nature of an improvement over the structure disclosed in my prior U.S. Pat. No. 3,670,159. In said prior patent, a light supporting frame is raised and lowered by means of a cable supported carriage, and automatically locked in place at the top of the tower or pole. To release the frame from its locked position, the carriage must be lowered to substantially ground level and latch releasing mechanism manually set, after which the carriage is again raised so that the latch releasing mechanism may unlock the frame for lowering movements to the ground where the lights may be serviced or replaced. Further, my earlier apparatus, like one disclosed in U.S. Pat. No. 3,856,639, issued to Rohn, et al., uses at least three cables for raising and lowering a light supporting unit, these being adjustably secured at inner ends, by means of a coupling device, to a single hoisting cable wound on a drum at the base of the pole or tower. Such coupling devices occupy needed space in a tower, and may rub against electrical conductors within the tower, creating a hazard.